In recent years, the development of a communication sheet that makes an electromagnetic wave travel using an interspace region sandwiched by a mesh-like conductor layer and a sheet-like conductor layer as a transmission path, and combines the electromagnetic wave with an electromagnetic wave in a leaching region leaked from the mesh-like conductor layer, thereby allowing for communication between devices (for example, Patent Literature 1), has been advanced.
As a utilization mode of such communication sheet, various applications that take advantage of features of the two-dimensionality of the communication sheet have been examined. For example, such a utilization mode has been considered where a communication sheet is arranged on a top board, such as a desk, and an information processing terminal, such as a personal computer, placed on the communication sheet performs communication through the communication sheet.
In this case, planarity is required for the communication sheet itself so as not to make the doing of general work at the desk inconvenient. Consequently, Patent Literature 2 to 4 disclose a method for arranging a communication interface device in accordance with a notch or an opening portion of a top board that has the notch and an opening, and supplying an electromagnetic wave to the communication sheet from below.
The communication sheet disclosed in Patent Literature 2 to 4 has a configuration provided with a mesh conductor surface at a lower side of a partial region of the communication sheet so as to be able to connect to the downwardly arranged communication interface device. As such communication sheet, a configuration is disclosed in which, for example, the communication sheet is cut so as to provide an opening in a center thereof, a cut portion is fitted in a remaining portion inside out, and thereby the mesh conductor surface is arranged at a lower side in the center. In addition, a configuration is disclosed in which an end of the communication sheet is cut in a notch shape, a cut portion is fitted in a remaining portion inside out, and thereby the mesh conductor surface is arranged at a lower side in the sheet end.
In addition, as the other utilization mode of the communication sheet, Patent Literature 5 discloses an RFID tag system that manages by a management device book etc. to which RFID (radio identification) tags have been attached using an electromagnetic wave transmission sheet (a communication sheet). The electromagnetic wave transmission sheet of Patent Literature 5 is set to be in a resonant condition by setting a length of a width perpendicular to a traveling direction of an electromagnetic wave to be transmitted as a length substantially equal to natural number times as long as a half-wave length of the electromagnetic wave to be transmitted, and thus reduction of leaked radio waves is achieved. Transmission and reception of a signal and power supply to the electromagnetic wave transmission sheet are performed through an interface arranged at one shorter side of the electromagnetic wave transmission sheet, or an interface arranged at a through hole provided inside of the electromagnetic wave transmission sheet. According to the electromagnetic wave transmission sheet, an electromagnetic wave utilization efficiency can be improved compared with a configuration in which an electromagnetic wave absorbing member for preventing electromagnetic wave leakage etc. is arranged at a sheet end.
In addition to this, Patent Literature 6 discloses a technology to configure an electromagnetic wave transmission medium system by mutually connecting and combining a plurality of electromagnetic wave transmission media in order to reduce a weight of an electromagnetic wave transmission medium (a communication sheet) having a large area and to facilitate the conveyance thereof. Here, as methods for connecting the plurality of electromagnetic wave transmission media, are disclosed a method for connecting one electromagnetic wave transmission medium and the other electromagnetic wave transmission medium by a pair of conductor plates that covers them so as to sandwich them from the front and the back, and a method for hollowing a part of one electromagnetic wave transmission medium, and fitting the other electromagnetic wave transmission medium in the hollowed part to thereby connect them.